Pumping gas

I have an 02 Hyundai Accent with over 100,000 miles. About 3 weeks ago, it started doing something weird. Whenever I try to fill it up with gas, it keeps shutting the pump off. I have to stand there and feed it in, very slowly. Can anyone tell me why this started happening and what I can do about it? Thanks.

Possibly some sort of restriction in the pipe leading to the tank? Next time it’s up on a lift, have them check for dents/kinks/etc.

If you have been in the habit of topping off the tank to get that last half gallon in there, you could be the cause of your problem. Doing that can damage the vent system (the charcoal filter) and cause cost you a few hundred dollars to fix it. Likely the owner’s manual and or a sticker on the car tells you not to do that.

As noted a mechanical problem with the vent system blocking the vent like a kinked hose or something dropped down the fill tube can cause it.

Good Luck

We get this question often, maybe even once a week for various cars, and not once has any poster come back and said “Hey guys I fixed it!” As a result, our entire panel of experts remains stumped over this all-too-common problem. All you get are guesses, some of them rather far-fetched.

Personally, I don’t buy into the damaged charcoal venting theory. Such a problem should light up the CEL on the dash. I think the most likely reason is a stuck valve in the filler hose or tank, some sort of float to prevent outflow in case the car overturned. I suggest trying to reopen this valve by poking a stiff wire (plastic weedcutter string?) all the way down before filling, possibly leaving it in place during fillup. Try it, and if it works, for pete’s sake let us know!

This is technically known as fill-up interuptus…the remedy is to pull out the filler tube slightly and continue to pump!

It could be the pump itself. My neighborhood gas station has 2 pumps that keep shutting off when I put the nozzle in all the way. When I have to use these pumps, I back the nozzle out a bit and everythong is fine. When I had the 1988 Caprice, all EXXON pumps in my area would shut off early, while Shell pumps were OK.

Steve, you’ve peiqued my curiosity. When the engine is off, no sensors are energized. If, when the gas cap is replaced and the engine started, the purge valve functions okay and the fumes are ingested, why would the CEL light trip? Certainly there would not be a leak.

If the charcoal bed is near saturation, the fumes in the tank can’t be breathed out in sufficient volume to allow the gas to be pumped in, and the filler nozzle is fitting into the tube such that the fumes can’t be readily drawn into the fill recovery system in sufficient volume, then the air would have no place to vent to and the pump would repeatedly shut off. But what would trip the CEL light? When the engine starts up, the volume that needs to go through the charcoal bed is miniscule compared to what it needs to be to fill the tank.

I’m not being disagreeable, but I think your point opens up some real good questions.

Well, there is an OBDII trouble code for a malfunctioning EVAP system.

See here: http://www.obd-codes.com/trouble_codes/generic/p0440-evaporative-emission-control-system-malfunction.php.

Dunno whether this type of malfunction would affect filling or not. It seems we are all guessing here.

Isn’t that known as The Masters and Johnson method?